A number of asymmetric reactions, including asymmetric reduction, have been developed, and various asymmetric metal complexes having optically active phosphine ligands as the catalyst that are used in these reactions, have been also reported. Among them, transition metal complexes, such as ruthenium, rhodium and iridium, coordinated with optically active nitrogen compounds, have excellent performance as catalysts for asymmetric synthesis reactions.
Thus, a number of various optically active nitrogen compounds have been developed heretofore, in order to enhance the performance of these catalysts (see Chem. Rev. (1992) p. 1051; J. Am. Chem. Soc. 117 (1995) p. 7562; J. Am. Chem. Soc. 118 (1996) p. 2521; J. Am. Chem. Soc. 118 (1996) p. 4916; and the like).